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A Discrete-Event Network Simulator
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API |
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A Discrete-Event Network Simulator
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API |
The Zipf distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically. More...
#include "random-variable-stream.h"
Inheritance diagram for ns3::ZipfRandomVariable: Collaboration diagram for ns3::ZipfRandomVariable:Public Member Functions | |
| ZipfRandomVariable () | |
| Creates a Zipf distribution RNG with the default values for n and alpha. | |
| double | GetAlpha () const |
| Returns the alpha value for the Zipf distribution returned by this RNG stream. | |
| virtual uint32_t | GetInteger () |
| Get the next random value drawn from the distribution. | |
| uint32_t | GetInteger (uint32_t n, uint32_t alpha) |
| Get the next random value drawn from the distribution. | |
| uint32_t | GetN () const |
| Returns the n value for the Zipf distribution returned by this RNG stream. | |
| double | GetValue () override |
| Get the next random value drawn from the distribution. | |
| double | GetValue (uint32_t n, double alpha) |
| Get the next random value drawn from the distribution. | |
| Public Member Functions inherited from ns3::RandomVariableStream | |
| RandomVariableStream () | |
| Default constructor. | |
| RandomVariableStream (const RandomVariableStream &)=delete | |
| ~RandomVariableStream () override | |
| Destructor. | |
| virtual uint32_t | GetInteger () |
| Get the next random value drawn from the distribution. | |
| int64_t | GetStream () const |
| Returns the stream number for the RngStream. | |
| virtual double | GetValue ()=0 |
| Get the next random value drawn from the distribution. | |
| bool | IsAntithetic () const |
| Check if antithetic values will be generated. | |
| RandomVariableStream & | operator= (const RandomVariableStream &)=delete |
| void | SetAntithetic (bool isAntithetic) |
| Specify whether antithetic values should be generated. | |
| void | SetStream (int64_t stream) |
| Specifies the stream number for the RngStream. | |
| Public Member Functions inherited from ns3::Object | |
| Object () | |
| Constructor. | |
| ~Object () override | |
| Destructor. | |
| void | AggregateObject (Ptr< Object > other) |
| Aggregate two Objects together. | |
| void | Dispose () |
| Dispose of this Object. | |
| AggregateIterator | GetAggregateIterator () const |
| Get an iterator to the Objects aggregated to this one. | |
| TypeId | GetInstanceTypeId () const override |
| Get the most derived TypeId for this Object. | |
| template<typename T > | |
| Ptr< T > | GetObject () const |
| Get a pointer to the requested aggregated Object. | |
| template<> | |
| Ptr< Object > | GetObject () const |
| Specialization of () for objects of type ns3::Object. | |
| template<typename T > | |
| Ptr< T > | GetObject (TypeId tid) const |
| Get a pointer to the requested aggregated Object by TypeId. | |
| template<> | |
| Ptr< Object > | GetObject (TypeId tid) const |
| Specialization of (TypeId tid) for objects of type ns3::Object. | |
| void | Initialize () |
| Invoke DoInitialize on all Objects aggregated to this one. | |
| bool | IsInitialized () const |
| Check if the object has been initialized. | |
| void | UnidirectionalAggregateObject (Ptr< Object > other) |
| Aggregate an Object to another Object. | |
| Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter > | |
| SimpleRefCount () | |
| Default constructor. | |
| SimpleRefCount (const SimpleRefCount &o) | |
| Copy constructor. | |
| uint32_t | GetReferenceCount () const |
| Get the reference count of the object. | |
| SimpleRefCount & | operator= (const SimpleRefCount &o) |
| Assignment operator. | |
| void | Ref () const |
| Increment the reference count. | |
| void | Unref () const |
| Decrement the reference count. | |
| Public Member Functions inherited from ns3::ObjectBase | |
| virtual | ~ObjectBase () |
| Virtual destructor. | |
| void | GetAttribute (std::string name, AttributeValue &value) const |
| Get the value of an attribute, raising fatal errors if unsuccessful. | |
| bool | GetAttributeFailSafe (std::string name, AttributeValue &value) const |
| Get the value of an attribute without raising errors. | |
| virtual TypeId | GetInstanceTypeId () const =0 |
| Get the most derived TypeId for this Object. | |
| void | SetAttribute (std::string name, const AttributeValue &value) |
| Set a single attribute, raising fatal errors if unsuccessful. | |
| bool | SetAttributeFailSafe (std::string name, const AttributeValue &value) |
| Set a single attribute without raising errors. | |
| bool | TraceConnect (std::string name, std::string context, const CallbackBase &cb) |
| Connect a TraceSource to a Callback with a context. | |
| bool | TraceConnectWithoutContext (std::string name, const CallbackBase &cb) |
| Connect a TraceSource to a Callback without a context. | |
| bool | TraceDisconnect (std::string name, std::string context, const CallbackBase &cb) |
| Disconnect from a TraceSource a Callback previously connected with a context. | |
| bool | TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb) |
| Disconnect from a TraceSource a Callback previously connected without a context. | |
Static Public Member Functions | |
| static TypeId | GetTypeId () |
| Register this type. | |
| Static Public Member Functions inherited from ns3::RandomVariableStream | |
| static TypeId | GetTypeId () |
| Register this type. | |
| Static Public Member Functions inherited from ns3::Object | |
| static TypeId | GetTypeId () |
| Register this type. | |
| Static Public Member Functions inherited from ns3::ObjectBase | |
| static TypeId | GetTypeId () |
| Get the type ID. | |
Private Attributes | |
| double | m_alpha |
| The alpha value for the Zipf distribution returned by this RNG stream. | |
| double | m_c |
| The normalization constant. | |
| uint32_t | m_n |
| The n value for the Zipf distribution returned by this RNG stream. | |
Additional Inherited Members | |
| Protected Member Functions inherited from ns3::RandomVariableStream | |
| RngStream * | Peek () const |
| Get the pointer to the underlying RngStream. | |
| Protected Member Functions inherited from ns3::Object | |
| Object (const Object &o) | |
| Copy an Object. | |
| virtual void | DoDispose () |
| Destructor implementation. | |
| virtual void | DoInitialize () |
| Initialize() implementation. | |
| virtual void | NotifyNewAggregate () |
| Notify all Objects aggregated to this one of a new Object being aggregated. | |
| Protected Member Functions inherited from ns3::ObjectBase | |
| void | ConstructSelf (const AttributeConstructionList &attributes) |
| Complete construction of ObjectBase; invoked by derived classes. | |
| virtual void | NotifyConstructionCompleted () |
| Notifier called once the ObjectBase is fully constructed. | |
| Related Functions inherited from ns3::ObjectBase | |
| static TypeId | GetObjectIid () |
| Ensure the TypeId for ObjectBase gets fully configured to anchor the inheritance tree properly. | |
The Zipf distribution Random Number Generator (RNG) that allows stream numbers to be set deterministically.
This class supports the creation of objects that return random numbers from a fixed Zipf distribution. It also supports the generation of single random numbers from various Zipf distributions.
Zipf's law states that given some corpus of natural language utterances, the frequency of any word is inversely proportional to its rank in the frequency table.
Zipf's distribution has two parameters, Alpha and N, where: 
The probability mass function is:
![\[
P(k; \alpha, N) = \frac{1}{k^\alpha H_{N,\alpha}}
\]](../../form_104_dark.png)
where the N-th generalized harmonic number is
![\[
H_{N,\alpha} = \sum_{m=1}^N \frac{1}{m^\alpha}
\]](../../form_105_dark.png)
Note the Zipf distribution is a discrete distribution, so the returned values 
The mean of the distribution is
![\[
\mu = \frac{H_{N,\alpha - 1}}{H_{N,\alpha}}
\]](../../form_107_dark.png)
The Zipf RNG value
![\[
u < \frac{H_k,\alpha}{H_N,\alpha}
\]](../../form_108_dark.png)
where 
Here is an example of how to use this class:
If an instance of this RNG is configured to return antithetic values, the actual value returned, 
![\[
1 - u < \frac{H_{k'},\alpha}{H_N,\alpha}
\]](../../form_110_dark.png)
ns3::ZipfRandomVariable is accessible through the following paths with Config::Set and Config::Connect:
No TraceSources are defined for this type.
Size of this type is 104 bytes (on a 64-bit architecture).
Definition at line 1642 of file random-variable-stream.h.
| ns3::ZipfRandomVariable::ZipfRandomVariable | ( | ) |
Creates a Zipf distribution RNG with the default values for n and alpha.
Definition at line 1315 of file random-variable-stream.cc.
References NS_LOG_FUNCTION.
| double ns3::ZipfRandomVariable::GetAlpha | ( | ) | const |
Returns the alpha value for the Zipf distribution returned by this RNG stream.
Definition at line 1329 of file random-variable-stream.cc.
References m_alpha, and NS_LOG_FUNCTION.
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virtual |
Get the next random value drawn from the distribution.
Reimplemented from ns3::RandomVariableStream.
Definition at line 155 of file random-variable-stream.cc.
Get the next random value drawn from the distribution.
| [in] | n | N value for the Zipf distribution. |
| [in] | alpha | Alpha value for the Zipf distribution. |
Definition at line 1369 of file random-variable-stream.cc.
References GetValue(), and NS_LOG_FUNCTION.
Here is the call graph for this function:| uint32_t ns3::ZipfRandomVariable::GetN | ( | ) | const |
Returns the n value for the Zipf distribution returned by this RNG stream.
Definition at line 1322 of file random-variable-stream.cc.
References m_n, and NS_LOG_FUNCTION.
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static |
Register this type.
Definition at line 1295 of file random-variable-stream.cc.
References m_alpha, m_n, ns3::MakeDoubleAccessor(), ns3::MakeIntegerAccessor(), and ns3::TypeId::SetParent().
Here is the call graph for this function:
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overridevirtual |
Get the next random value drawn from the distribution.
Implements ns3::RandomVariableStream.
Definition at line 1376 of file random-variable-stream.cc.
References GetValue(), m_alpha, m_n, and NS_LOG_FUNCTION.
Referenced by GetInteger(), and GetValue().
Here is the call graph for this function: Here is the caller graph for this function:Get the next random value drawn from the distribution.
| [in] | n | N value for the Zipf distribution. |
| [in] | alpha | Alpha value for the Zipf distribution. |
Definition at line 1336 of file random-variable-stream.cc.
References ns3::RandomVariableStream::IsAntithetic(), m_alpha, m_c, m_n, NS_LOG_FUNCTION, ns3::RandomVariableStream::Peek(), and ns3::RngStream::RandU01().
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private |
The alpha value for the Zipf distribution returned by this RNG stream.
Definition at line 1689 of file random-variable-stream.h.
Referenced by GetAlpha(), GetTypeId(), and GetValue().
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private |
The normalization constant.
Definition at line 1692 of file random-variable-stream.h.
Referenced by GetValue().
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private |
The n value for the Zipf distribution returned by this RNG stream.
Definition at line 1686 of file random-variable-stream.h.
Referenced by GetN(), GetTypeId(), and GetValue().
1.9.6